SIXTH MEDITATION: the Existence of Material Things, and the Real Distinction Between Mind and Body

1 SIXTH MEDITATION: The existence of material things, and the real distinction between mind and body The remaining task is to consider whether material things exist. Insofar as they are the subject matter of pure mathematics, I perceive them clearly and distinctly; so I at least know that they could exist, because anything that I perceive in that way could be created by God. (The only reason I have ever accepted for thinking that something could not be made by him is that there would be a contradiction in my perceiving it distinctly.) My faculty of imagination, which I am aware of using when I turn my mind to material things, also suggests that they really exist. For when I think harder about what imagination is, it seems to be simply an application of the faculty of knowing to a body that is intimately present to it – and that has to be a body that exists. To make this clear, I will first examine how imagination differs from pure understanding. When I imagine a triangle, for example, I don’t merely understand that it is a three- sided figure, but I also see the three lines with my mind’s eye as if they were present to me; that is what imagining is. But if I think of a chiliagon, although I understand quite well that it is a figure with a thousand sides, I don’t imagine the thousand sides or see them as if they were present to me. When I think of a body, I usually form some kind of image; so in thinking of a chiliagon I may construct in my mind – strictly speaking, in my imagination – a confused representation of some figure. But obviously it won’t be a chiliagon, for it is the very same image that I would form if I were thinking of, say, a figure with ten thousand sides. So it wouldn’t help me to recognize the properties that distinguish a chiliagon from other many-sided figures. In the case of a pentagon, the situation is different. I can of course understand this figure without the help of the imagination (just as I can understand a chiliagon); but I can also imagine a pentagon, by applying my mind’s eye to its five sides and the area they enclose. This imagining, I find, takes more mental effort than understanding does; and that is enough to show that imagination is different from pure understanding. Being able to imagine isn’t essential to me, as being able to understand is; for even if I had no power of imagination I would still be the same individual that I am. This seems to imply that my power of imagining depends on something other than myself; and I can easily understand that if there is such a thing as my body – that is, if my mind is joined to a certain body in such a way that it can contemplate that 2 body whenever it wants to – then it might be this very body that enables me to imagine corporeal things. So it may be that imagining differs from pure understanding purely like this: when the mind understands, it somehow turns in on itself and inspects one of its own ideas; but when it imagines, it turns away from itself and looks at something in the body (something that conforms to an idea – either one understood by the mind or one perceived by the senses). I can, I repeat, easily see that this might be how imagination comes about if the body exists; and since I can think of no other equally good way of explaining what imagination is, I can conjecture that the body exists. But this is only a probability. Even after all my careful enquiry I still can’t see how, on the basis of the idea of corporeal nature that I find in my imagination, to prove for sure that some body exists. As well as the corporeal nature that is the subject-matter of pure mathematics, I am also accustomed to imagining colours, sounds, tastes, pain and so on – though not so distinctly. Now, I perceive these much better by means of the senses, which is how (helped by memory) they appear to have reached the imagination. So in order to deal with them more fully, I must attend to the senses – that is, to the kind of thinking that I call ‘sensory perception’. I want to know whether the things that are perceived through the senses provide me with any sure argument for the existence of bodies. To begin with, I will (1) go back over everything that I originally took to be perceived by the senses, and reckoned to be true; and I will go over my reasons for thinking this. Next, I will (2) set out my reasons for later doubting these things. Finally, I will (3) consider what I should now believe about them. (1) First of all then, I perceived by my senses that I had a head, hands, feet and other limbs making up the body that I regarded as part of myself, or perhaps even as my whole self. I also perceived by my senses that this body was situated among many other bodies that could harm or help it; and I detected the favourable effects by a sensation of pleasure and the unfavourable ones by pain. As well as pain and pleasure, I also had sensations of hunger, thirst, and other such appetites, and also of bodily states tending towards cheerfulness, sadness, anger and similar emotions. Outside myself, besides the extension, shapes and movements of bodies, I also had sensations of their hardness and heat, and of the other qualities that can be known by touch. In addition, I had sensations of light, colours, smells, tastes and sounds, and differences amongst these enabled me to sort out the sky, the earth, the seas and other bodies from one another. All I was immediately aware of in each case were my ideas, but it was reasonable for me to think that what I was perceiving through the senses were external bodies that caused the ideas. For I found that 3 these ideas came to me quite without my consent: I couldn’t have that kind of idea of any object, even if I wanted to, if the object was not present to my sense organs; and I couldn’t avoid having the idea when the object was present. Also, since the ideas that came through the senses were much more lively and vivid and sharp than ones that I formed voluntarily when thinking about things, and than ones that I found impressed on my memory, it seemed impossible that sensory ideas were coming from within me; so I had to conclude that they came from external things. My only way of knowing about these things was through the ideas themselves, so it was bound to occur to me that the things might resemble the ideas. In addition, I remembered that I had the use of my senses before I ever had the use of reason; and I saw that the ideas that I formed were, for the most part, made up of elements of sensory ideas. This convinced me that I had nothing at all in my intellect that I had not previously had in sensation. As for the body that by some special right I called ‘mine’: I had reason to think that it belonged to me in a way that no other body did. There were three reasons for this. I could never be separated from it, as I could from other bodies; I felt all my appetites and emotions in it and on account of it; and I was aware of pain and pleasurable ticklings in parts of this body but not in any other body. But why should that curious sensation of pain give rise to a particular distress of mind; and why should a certain kind of delight follow on a tickling sensation? Again, why should that curious tugging in the stomach that I call ‘hunger’ tell me that I should eat, or a dryness of the throat tell me to drink, and so on? I couldn’t explain any of this, except to say that nature taught me so. For there is no connection (or none that I understand) between the tugging sensation and the decision to eat, or between the sensation of something causing pain and the mental distress that arises from it. It seems that nature taught me to make these judgments about objects of the senses, for I was making them before I had any arguments to support them. (2) Later on, however, my experiences gradually undermined all my faith in the senses. A tower that had looked round from a distance appeared square from close up; an enormous statue standing on a high column didn’t look large from the ground. In countless such cases I found that the judgments of the external senses were mistaken, and the same was true of the internal senses. What can be more internal than pain? Yet I heard that an amputee might occasionally seem to feel pain in the missing limb. So even in my own case, I had to conclude, it was not quite certain that a particular limb was hurting, even if I felt pain in it. To these reasons for doubting, I recently added two very general ones. The first was that every sensory experience I ever thought I was having while 4 awake I can also think of myself as having while asleep; and since I don’t believe that what I seem to perceive in sleep comes from things outside me, I didn’t see why I should be any more inclined to believe this of what I think I perceive while awake.

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